The country is going through its biggest whooping cough outbreak in decades, and researchers recently discovered why. Recent studies show that vaccines developed in the 1990s are losing their effectiveness much more quickly than first thought. After receiving a vaccine at age six, it was recommended that children get a booster sometime in between 11 and 18 years of age.

But with the recent findings, Judi Van Hulzen, a nurse at Marion County Public Health, says those boosters should be coming much closer to the beginning of that window. She recommends that kids get that booster between 11 and 13, adding that the Iowa legislature is now considering making that booster vaccine mandatory before seventh grade. Van Hulzen says to talk to your doctor if you have any questions.